The present disclosure relates to a touch panel and a touchscreen device including the same.
A touchscreen device such as a touchscreen or a touch pad is a data input device attached to a display device so as to provide an intuitive user interface, and has recently been widely applied to various electronic devices such as cellular phones, personal digital assistants (PDA), and a navigation devices. Particularly, as demand for smartphones has recently increased, touchscreens have been increasingly employed as devices able to provide users with various methods of data input in a limited form factor.
Touchscreens used in portable devices may be mainly divided into resistive type touchscreens and capacitive type touchscreens, depending on the manner in which touches are sensed therein. Capacitive type touchscreens have the advantages of a relatively long lifespan and ease of implementation of various data input schemes and gestures, and thus capacitive type touchscreens have been increasingly employed. The implementation of a multi-touch interface is particularly easy in capacitive type touchscreens, as compared to resistive type touchscreens, and thus, capacitive type touchscreens are widely used in devices such as smartphones and the like.
Capacitive type touchscreens include a plurality of electrodes having a predetermined pattern and the electrodes define a plurality of nodes in which changes in capacitance are generated due to touches. The nodes deployed on a two-dimensional plane generate changes in self-capacitance or changes in mutual-capacitance due to touches. Coordinates of the touches may be calculated by applying a weighted average calculation method or the like to the changes capacitance formed in the nodes.
In existing touch panels, sensing electrodes for sensing touches are commonly formed of indium tin oxide (ITO). In the case of ITO, however, indium is a rare-earth element and is thus relatively expensive, such that it is not cost competitive. Further, world indium reserves are expected to be depleted within the next decade, and thus, a stable supply of indium may not be readily available. For these reasons, research into forming an electrode using opaque fine conductive lines is on-going. Electrodes formed using fine conductive lines formed of a material such as metal are advantageous in that it has much better electric conductivity than ITO or conductive polymer and it is easily available.
Recently, applications that allow touchscreen devices to detect a stylus pen or various types of gesture have being developed to allow for greater user convenience. To this end, an electrode structure capable of detecting minute changes in capacitance is required.